Regex Tester

To test a regular expression, type the pattern and flags (g, i, m, s, u, y) and paste a test string: every match is highlighted live with its position and capture groups, and you can preview replacements with $1 references.

Read the guide

Free
No signup
Runs in your browser

Pattern

/gi

Test string

Contact ana@example.com or bo@test.com. Not: charlie@site.org

2 matches

#	Index	Match	Groups
1	8	ana@example.com	$1: ana, $2: example
2	27	bo@test.com	$1: bo, $2: test

Cheat sheet

.	Any character except newline
\d \w \s	Digit, word character, whitespace
[abc] [^abc]	Any of / none of
^ $	Start / end of line (with m)
* + ? {2,5}	0+, 1+, 0 or 1, between 2 and 5
*? +?	Lazy (as few as possible)
(…) (?<name>…)	Capture group / named group
(?:…)	Non-capturing group
(?=…) (?!…)	Lookahead / negative lookahead
(?<=…) (?<!…)	Lookbehind / negative lookbehind
\b	Word boundary
\p{L}	Any letter (needs u flag)

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How to use Regex Tester

1Type or paste your input into the Regex Tester.
2Choose any options you need.
3See the result update instantly.
4Copy the result or download it.

Regex Tester: questions people ask

Which regex flavour is used?

JavaScript (ECMAScript 2024), the same engine as your browser and Node.js, including lookbehind, named groups and Unicode property escapes.

Why does my pattern freeze?

Some patterns backtrack catastrophically, for example (a+)+$. The tester stops after a time limit and warns you.

Is my data uploaded when I use the Regex Tester?

No. The Regex Tester runs entirely in your web browser, so your text and numbers stay on your device and work even on a slow connection.

Does the Regex Tester work on iPhone, Android and Mac?

Yes. The Regex Tester runs in any modern browser (Safari, Chrome, Edge or Firefox) on iPhone, iPad, Android phones, Mac, Windows and Chromebook. There is no app to install.

Is the Regex Tester free?

Yes. The Regex Tester is free with no signup, no watermark and no daily limit.